The reaction between NO3 and HO2 is one of the most important reaction in nighttime atmospheric chemistry. There are two pathways for this reaction: one leading to the formation of HNO3, and the other resulting in the formation of the OH radical. Recent experimental and theoretical studies suggest that this reaction occurs through only the OH radical pathway. In this work, we have investigated the fate of this reaction in the presence of water using high-level quantum chemical and kinetics calculations over the temperature range of 213-400 K. Our investigation suggests that even in the presence of a water monomer, the reaction predominantly produces OH radicals.